how2 set date/time

hi,
I installed some days ago koppix 6.7.3 in a VM, and today recognized, that time and date always shows the date/time from installationday. Therefore usenetpostings sent via knode to newsserver were cancelt because time/date are too old for acceptance. Trying to set up time/date manually via preferences failed and knoppix says, that I am not authorized to do this. No password will be asked, which should be necessary to become su for doing sysemchanges.
Whats to do, to make a timeserver work for knoppix to set right time/date?

regards
rudiratlos

The question got answer in German Forum.
Problem caused by differnt settings of UTC within Host and Guest.